path: root/pkgs/development/compilers/zig/002-0.10-macho-fixes.patch

From 405801d8a8be734425eca4f3eebc56287804ac93 Mon Sep 17 00:00:00 2001
From: Jakub Konka <kubkon@jakubkonka.com>
Date: Sun, 5 Feb 2023 10:04:34 +0100
Subject: [PATCH] macho: temp fix alignment and enable some logs

---
 src/link/MachO/Object.zig  | 80 ++++++++++++++++++++++++++------------
 src/link/MachO/ZldAtom.zig | 29 +++++++-------
 src/link/MachO/zld.zig     | 22 +++++------
 3 files changed, 79 insertions(+), 52 deletions(-)

diff --git a/src/link/MachO/Object.zig b/src/link/MachO/Object.zig
index 401184da515..05638c1f858 100644
--- a/src/link/MachO/Object.zig
+++ b/src/link/MachO/Object.zig
@@ -54,12 +54,18 @@ atom_by_index_table: []AtomIndex = undefined,
 /// Can be undefined as set together with in_symtab.
 globals_lookup: []i64 = undefined,
 
+/// All relocs sorted and flattened.
+relocs: std.ArrayListUnmanaged(macho.relocation_info) = .{},
+sect_relocs_lookup: std.ArrayListUnmanaged(u32) = .{},
+
 atoms: std.ArrayListUnmanaged(AtomIndex) = .{},
 
 pub fn deinit(self: *Object, gpa: Allocator) void {
     self.atoms.deinit(gpa);
     gpa.free(self.name);
     gpa.free(self.contents);
+    self.relocs.deinit(gpa);
+    self.sect_relocs_lookup.deinit(gpa);
     if (self.in_symtab) |_| {
         gpa.free(self.source_symtab_lookup);
         gpa.free(self.source_address_lookup);
@@ -101,6 +107,10 @@ pub fn parse(self: *Object, allocator: Allocator, cpu_arch: std.Target.Cpu.Arch)
         return error.MismatchedCpuArchitecture;
     }
 
+    const nsects = self.getSourceSections().len;
+    try self.sect_relocs_lookup.resize(allocator, nsects);
+    mem.set(u32, self.sect_relocs_lookup.items, 0);
+
     var it = LoadCommandIterator{
         .ncmds = self.header.ncmds,
         .buffer = self.contents[@sizeOf(macho.mach_header_64)..][0..self.header.sizeofcmds],
@@ -110,13 +120,11 @@ pub fn parse(self: *Object, allocator: Allocator, cpu_arch: std.Target.Cpu.Arch)
             .SYMTAB => {
                 const symtab = cmd.cast(macho.symtab_command).?;
                 self.in_symtab = @ptrCast(
-                    [*]const macho.nlist_64,
-                    @alignCast(@alignOf(macho.nlist_64), &self.contents[symtab.symoff]),
+                    [*]align(1) const macho.nlist_64,
+                    self.contents.ptr + symtab.symoff,
                 )[0..symtab.nsyms];
                 self.in_strtab = self.contents[symtab.stroff..][0..symtab.strsize];
 
-                const nsects = self.getSourceSections().len;
-
                 self.symtab = try allocator.alloc(macho.nlist_64, self.in_symtab.?.len + nsects);
                 self.source_symtab_lookup = try allocator.alloc(u32, self.in_symtab.?.len);
                 self.strtab_lookup = try allocator.alloc(u32, self.in_symtab.?.len);
@@ -192,6 +200,17 @@ const SymbolAtIndex = struct {
         return mem.sliceTo(@ptrCast([*:0]const u8, ctx.in_strtab.?.ptr + off), 0);
     }
 
+    fn getSymbolSeniority(self: SymbolAtIndex, ctx: Context) u2 {
+        const sym = self.getSymbol(ctx);
+        if (!sym.ext()) {
+            const sym_name = self.getSymbolName(ctx);
+            if (mem.startsWith(u8, sym_name, "l") or mem.startsWith(u8, sym_name, "L")) return 0;
+            return 1;
+        }
+        if (sym.weakDef() or sym.pext()) return 2;
+        return 3;
+    }
+
     /// Performs lexicographic-like check.
     /// * lhs and rhs defined
     ///   * if lhs == rhs
@@ -206,23 +225,15 @@ const SymbolAtIndex = struct {
         if (lhs.sect() and rhs.sect()) {
             if (lhs.n_value == rhs.n_value) {
                 if (lhs.n_sect == rhs.n_sect) {
-                    if (lhs.ext() and rhs.ext()) {
-                        if ((lhs.pext() or lhs.weakDef()) and (rhs.pext() or rhs.weakDef())) {
-                            return false;
-                        } else return rhs.pext() or rhs.weakDef();
-                    } else {
-                        const lhs_name = lhs_index.getSymbolName(ctx);
-                        const lhs_temp = mem.startsWith(u8, lhs_name, "l") or mem.startsWith(u8, lhs_name, "L");
-                        const rhs_name = rhs_index.getSymbolName(ctx);
-                        const rhs_temp = mem.startsWith(u8, rhs_name, "l") or mem.startsWith(u8, rhs_name, "L");
-                        if (lhs_temp and rhs_temp) {
-                            return false;
-                        } else return rhs_temp;
-                    }
+                    const lhs_senior = lhs_index.getSymbolSeniority(ctx);
+                    const rhs_senior = rhs_index.getSymbolSeniority(ctx);
+                    if (lhs_senior == rhs_senior) {
+                        return lessThanByNStrx(ctx, lhs_index, rhs_index);
+                    } else return lhs_senior < rhs_senior;
                 } else return lhs.n_sect < rhs.n_sect;
             } else return lhs.n_value < rhs.n_value;
         } else if (lhs.undf() and rhs.undf()) {
-            return false;
+            return lessThanByNStrx(ctx, lhs_index, rhs_index);
         } else return rhs.undf();
     }
 
@@ -393,6 +404,16 @@ pub fn splitIntoAtoms(self: *Object, zld: *Zld, object_id: u31) !void {
             zld.sections.items(.header)[out_sect_id].sectName(),
         });
 
+        // Parse all relocs for the input section, and sort in descending order.
+        // Previously, I have wrongly assumed the compilers output relocations for each
+        // section in a sorted manner which is simply not true.
+        const start = @intCast(u32, self.relocs.items.len);
+        if (self.getSourceRelocs(section.header)) |relocs| {
+            try self.relocs.appendUnalignedSlice(gpa, relocs);
+            std.sort.sort(macho.relocation_info, self.relocs.items[start..], {}, relocGreaterThan);
+        }
+        self.sect_relocs_lookup.items[section.id] = start;
+
         const cpu_arch = zld.options.target.cpu.arch;
         const sect_loc = filterSymbolsBySection(symtab[sect_sym_index..], sect_id + 1);
         const sect_start_index = sect_sym_index + sect_loc.index;
@@ -559,7 +580,7 @@ pub fn getSourceSections(self: Object) []const macho.section_64 {
     } else unreachable;
 }
 
-pub fn parseDataInCode(self: Object) ?[]const macho.data_in_code_entry {
+pub fn parseDataInCode(self: Object) ?[]align(1) const macho.data_in_code_entry {
     var it = LoadCommandIterator{
         .ncmds = self.header.ncmds,
         .buffer = self.contents[@sizeOf(macho.mach_header_64)..][0..self.header.sizeofcmds],
@@ -569,10 +590,7 @@ pub fn parseDataInCode(self: Object) ?[]const macho.data_in_code_entry {
             .DATA_IN_CODE => {
                 const dice = cmd.cast(macho.linkedit_data_command).?;
                 const ndice = @divExact(dice.datasize, @sizeOf(macho.data_in_code_entry));
-                return @ptrCast(
-                    [*]const macho.data_in_code_entry,
-                    @alignCast(@alignOf(macho.data_in_code_entry), &self.contents[dice.dataoff]),
-                )[0..ndice];
+                return @ptrCast([*]align(1) const macho.data_in_code_entry, self.contents.ptr + dice.dataoff)[0..ndice];
             },
             else => {},
         }
@@ -632,11 +650,23 @@ pub fn getSectionAliasSymbolPtr(self: *Object, sect_id: u8) *macho.nlist_64 {
     return &self.symtab[self.getSectionAliasSymbolIndex(sect_id)];
 }
 
-pub fn getRelocs(self: Object, sect: macho.section_64) []align(1) const macho.relocation_info {
-    if (sect.nreloc == 0) return &[0]macho.relocation_info{};
+fn getSourceRelocs(self: Object, sect: macho.section_64) ?[]align(1) const macho.relocation_info {
+    if (sect.nreloc == 0) return null;
     return @ptrCast([*]align(1) const macho.relocation_info, self.contents.ptr + sect.reloff)[0..sect.nreloc];
 }
 
+pub fn getRelocs(self: Object, sect_id: u16) []const macho.relocation_info {
+    const sect = self.getSourceSection(sect_id);
+    const start = self.sect_relocs_lookup.items[sect_id];
+    const len = sect.nreloc;
+    return self.relocs.items[start..][0..len];
+}
+
+fn relocGreaterThan(ctx: void, lhs: macho.relocation_info, rhs: macho.relocation_info) bool {
+    _ = ctx;
+    return lhs.r_address > rhs.r_address;
+}
+
 pub fn getSymbolName(self: Object, index: u32) []const u8 {
     const strtab = self.in_strtab.?;
     const sym = self.symtab[index];
diff --git a/src/link/MachO/ZldAtom.zig b/src/link/MachO/ZldAtom.zig
index 817aa816625..b42309598d7 100644
--- a/src/link/MachO/ZldAtom.zig
+++ b/src/link/MachO/ZldAtom.zig
@@ -465,7 +465,7 @@ pub fn resolveRelocs(
     zld: *Zld,
     atom_index: AtomIndex,
     atom_code: []u8,
-    atom_relocs: []align(1) const macho.relocation_info,
+    atom_relocs: []const macho.relocation_info,
     reverse_lookup: []u32,
 ) !void {
     const arch = zld.options.target.cpu.arch;
@@ -540,7 +540,7 @@ fn resolveRelocsArm64(
     zld: *Zld,
     atom_index: AtomIndex,
     atom_code: []u8,
-    atom_relocs: []align(1) const macho.relocation_info,
+    atom_relocs: []const macho.relocation_info,
     reverse_lookup: []u32,
     context: RelocContext,
 ) !void {
@@ -579,7 +579,6 @@ fn resolveRelocsArm64(
         }
 
         const target = parseRelocTarget(zld, atom_index, rel, reverse_lookup);
-        const rel_offset = @intCast(u32, rel.r_address - context.base_offset);
 
         log.debug("  RELA({s}) @ {x} => %{d} ('{s}') in object({?})", .{
             @tagName(rel_type),
@@ -589,6 +588,7 @@ fn resolveRelocsArm64(
             target.file,
         });
 
+        const rel_offset = @intCast(u32, rel.r_address - context.base_offset);
         const source_addr = blk: {
             const source_sym = zld.getSymbol(atom.getSymbolWithLoc());
             break :blk source_sym.n_value + rel_offset;
@@ -596,7 +596,7 @@ fn resolveRelocsArm64(
         const is_tlv = is_tlv: {
             const source_sym = zld.getSymbol(atom.getSymbolWithLoc());
             const header = zld.sections.items(.header)[source_sym.n_sect - 1];
-            break :is_tlv header.@"type"() == macho.S_THREAD_LOCAL_VARIABLES;
+            break :is_tlv header.type() == macho.S_THREAD_LOCAL_VARIABLES;
         };
         const target_addr = try getRelocTargetAddress(zld, rel, target, is_tlv);
 
@@ -831,7 +831,7 @@ fn resolveRelocsX86(
     zld: *Zld,
     atom_index: AtomIndex,
     atom_code: []u8,
-    atom_relocs: []align(1) const macho.relocation_info,
+    atom_relocs: []const macho.relocation_info,
     reverse_lookup: []u32,
     context: RelocContext,
 ) !void {
@@ -877,7 +877,7 @@ fn resolveRelocsX86(
         const is_tlv = is_tlv: {
             const source_sym = zld.getSymbol(atom.getSymbolWithLoc());
             const header = zld.sections.items(.header)[source_sym.n_sect - 1];
-            break :is_tlv header.@"type"() == macho.S_THREAD_LOCAL_VARIABLES;
+            break :is_tlv header.type() == macho.S_THREAD_LOCAL_VARIABLES;
         };
 
         log.debug("    | source_addr = 0x{x}", .{source_addr});
@@ -1015,27 +1015,24 @@ pub fn getAtomCode(zld: *Zld, atom_index: AtomIndex) []const u8 {
     return code[offset..][0..code_len];
 }
 
-pub fn getAtomRelocs(zld: *Zld, atom_index: AtomIndex) []align(1) const macho.relocation_info {
+pub fn getAtomRelocs(zld: *Zld, atom_index: AtomIndex) []const macho.relocation_info {
     const atom = zld.getAtomPtr(atom_index);
     assert(atom.getFile() != null); // Synthetic atom shouldn't need to unique for relocs.
     const object = zld.objects.items[atom.getFile().?];
 
-    const source_sect = if (object.getSourceSymbol(atom.sym_index)) |source_sym| blk: {
-        const source_sect = object.getSourceSection(source_sym.n_sect - 1);
-        assert(!source_sect.isZerofill());
-        break :blk source_sect;
+    const source_sect_id = if (object.getSourceSymbol(atom.sym_index)) |source_sym| blk: {
+        break :blk source_sym.n_sect - 1;
     } else blk: {
         // If there was no matching symbol present in the source symtab, this means
         // we are dealing with either an entire section, or part of it, but also
         // starting at the beginning.
         const nbase = @intCast(u32, object.in_symtab.?.len);
         const sect_id = @intCast(u16, atom.sym_index - nbase);
-        const source_sect = object.getSourceSection(sect_id);
-        assert(!source_sect.isZerofill());
-        break :blk source_sect;
+        break :blk sect_id;
     };
-
-    const relocs = object.getRelocs(source_sect);
+    const source_sect = object.getSourceSection(source_sect_id);
+    assert(!source_sect.isZerofill());
+    const relocs = object.getRelocs(source_sect_id);
 
     if (atom.cached_relocs_start == -1) {
         const indexes = if (object.getSourceSymbol(atom.sym_index)) |source_sym| blk: {
diff --git a/src/link/MachO/zld.zig b/src/link/MachO/zld.zig
index 3a2ea79c6ec..cee3f302c08 100644
--- a/src/link/MachO/zld.zig
+++ b/src/link/MachO/zld.zig
@@ -396,7 +396,7 @@ pub const Zld = struct {
                 break :blk null;
             }
 
-            switch (sect.@"type"()) {
+            switch (sect.type()) {
                 macho.S_4BYTE_LITERALS,
                 macho.S_8BYTE_LITERALS,
                 macho.S_16BYTE_LITERALS,
@@ -1701,7 +1701,7 @@ pub const Zld = struct {
                             break :outer;
                         }
                     }
-                    switch (header.@"type"()) {
+                    switch (header.type()) {
                         macho.S_NON_LAZY_SYMBOL_POINTERS => {
                             try self.writeGotPointer(count, buffer.writer());
                         },
@@ -1718,7 +1718,7 @@ pub const Zld = struct {
                                     break :outer;
                                 }
                             }
-                            if (header.@"type"() == macho.S_SYMBOL_STUBS) {
+                            if (header.type() == macho.S_SYMBOL_STUBS) {
                                 try self.writeStubCode(atom_index, count, buffer.writer());
                             } else if (mem.eql(u8, header.sectName(), "__stub_helper")) {
                                 try self.writeStubHelperCode(atom_index, buffer.writer());
@@ -1802,7 +1802,7 @@ pub const Zld = struct {
         for (slice.items(.header)) |*header, sect_id| {
             if (header.size == 0) continue;
             if (self.requiresThunks()) {
-                if (header.isCode() and !(header.@"type"() == macho.S_SYMBOL_STUBS) and !mem.eql(u8, header.sectName(), "__stub_helper")) continue;
+                if (header.isCode() and !(header.type() == macho.S_SYMBOL_STUBS) and !mem.eql(u8, header.sectName(), "__stub_helper")) continue;
             }
 
             var atom_index = slice.items(.first_atom_index)[sect_id];
@@ -1830,7 +1830,7 @@ pub const Zld = struct {
         if (self.requiresThunks()) {
             for (slice.items(.header)) |header, sect_id| {
                 if (!header.isCode()) continue;
-                if (header.@"type"() == macho.S_SYMBOL_STUBS) continue;
+                if (header.type() == macho.S_SYMBOL_STUBS) continue;
                 if (mem.eql(u8, header.sectName(), "__stub_helper")) continue;
 
                 // Create jump/branch range extenders if needed.
@@ -1994,10 +1994,10 @@ pub const Zld = struct {
         const section_precedence: u4 = blk: {
             if (header.isCode()) {
                 if (mem.eql(u8, "__text", header.sectName())) break :blk 0x0;
-                if (header.@"type"() == macho.S_SYMBOL_STUBS) break :blk 0x1;
+                if (header.type() == macho.S_SYMBOL_STUBS) break :blk 0x1;
                 break :blk 0x2;
             }
-            switch (header.@"type"()) {
+            switch (header.type()) {
                 macho.S_NON_LAZY_SYMBOL_POINTERS,
                 macho.S_LAZY_SYMBOL_POINTERS,
                 => break :blk 0x0,
@@ -2121,7 +2121,7 @@ pub const Zld = struct {
 
         // Finally, unpack the rest.
         for (slice.items(.header)) |header, sect_id| {
-            switch (header.@"type"()) {
+            switch (header.type()) {
                 macho.S_LITERAL_POINTERS,
                 macho.S_REGULAR,
                 macho.S_MOD_INIT_FUNC_POINTERS,
@@ -2252,7 +2252,7 @@ pub const Zld = struct {
         // Finally, unpack the rest.
         const slice = self.sections.slice();
         for (slice.items(.header)) |header, sect_id| {
-            switch (header.@"type"()) {
+            switch (header.type()) {
                 macho.S_LITERAL_POINTERS,
                 macho.S_REGULAR,
                 macho.S_MOD_INIT_FUNC_POINTERS,
@@ -2707,10 +2707,10 @@ pub const Zld = struct {
     }
 
     fn filterDataInCode(
-        dices: []const macho.data_in_code_entry,
+        dices: []align(1) const macho.data_in_code_entry,
         start_addr: u64,
         end_addr: u64,
-    ) []const macho.data_in_code_entry {
+    ) []align(1) const macho.data_in_code_entry {
         const Predicate = struct {
             addr: u64,